This will differ from job to job, however they will also look at different aspects of your CV. Therefore if you work hard to achieve good grades in your modules, 1st year, 2nd year etc., this will illustrate your qualities as a candidate!
A levels only form part of the application process for internships. Good University grades will always contribute positively to your application as it shows improvement through the pass years. You can always try to boost your application by participating in extra-curricular events. This could include things like volunteering, work experience (online or in person) etc. that show case interest in their area of work.
Hope this helps. Chloe -University of Kent Student Rep